Tecnoseal Shaft Anode - Zinc - 1-3/4" Shaft Diameter. These Boating & Marine from Tecnoseal protect propeller shafts and rudders from the inside out by binding nitrogen gas to the anode which prevents the formation of zinc salts which would otherwise cause pitting and corrosion. The Tecnoseal X8 Prop Shaft Anode features a 3.20" outer diameter and 1.75" inner diameter with 4 fixing holes for the best security on your boat. Pick up your Tecnoseal X8 Saltwater Shaft Anode to preserve and prolong the life of your boat's propellers and rudders. Specifications for Tecnoseal X8 Shaft Anode: Manufacturer: Tecnoseal Color: Zinc Package Contents: Tecnoseal X8 Shaft Anode Tecnoseal X8: X8 Shaft Anode - Zinc - 1-3/4" Shaft Diameter